A floor pan of a vehicle may be welded to a side sill in the prior art, as illustrated in FIG. 1. In a side impact, such as a side impact with a pole, severe deformation of the vehicle underbody structure may occur. The severe deformation can result in the floor pan “F” separating from the side sill “S”, tearing of the floor pan “F” or tearing from other structural members.
Resistance welds, or spot welds, are normally used to attach the floor pan to the side sill and kick-up cross members. In a side impact, spot welds are subjected to complex loading due to shear loading, relative displacement between the floor pan and side sill, in-plane rotation about the weld or tensile loading. Such loading may be due to separating forces applied between adjacent sheet metal parts in a direction normal to the metal sheets. These types of complex loads may result in spot weld failure.
In addition, material failure during a side impact may be caused by severe deformation of underbody structural members and of the floor pan. Deformation of the floor pan may exceed the material elongation limits in some side impacts.
This disclosure is directed to solving the above problems and other problems as summarized below.